The branch releng/13.1 has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=1544cd332b9635a4a3c1821d895c3ad40bc630f9
commit 1544cd332b9635a4a3c1821d895c3ad40bc630f9 Author: Mateusz Guzik <[email protected]> AuthorDate: 2022-03-25 15:04:04 +0000 Commit: Mateusz Guzik <[email protected]> CommitDate: 2022-03-29 12:40:32 +0000 amd64: bring back asm bcmp, shared with memcmp Turns out clang converts "memcmp(foo, bar, len) == 0" and similar to bcmp calls. Reviewed by: emaste (previous version), jhb (previous version) Differential Revision: https://reviews.freebsd.org/D34673 Approved by: re (gjb) (cherry picked from commit fbc002cb72d2d9bb435cce99630d5d7da9f59390) (cherry picked from commit c5890784f6d315c501586b39cf8c0c80b609be5b) --- lib/libc/amd64/string/bcmp.S | 122 ++--------------------------------------- lib/libc/amd64/string/memcmp.S | 26 ++++++++- 2 files changed, 28 insertions(+), 120 deletions(-) diff --git a/lib/libc/amd64/string/bcmp.S b/lib/libc/amd64/string/bcmp.S index efdc6d33e4dd..f7a4603f6c5a 100644 --- a/lib/libc/amd64/string/bcmp.S +++ b/lib/libc/amd64/string/bcmp.S @@ -1,121 +1,7 @@ /*- - * Copyright (c) 2018 The FreeBSD Foundation - * - * This software was developed by Mateusz Guzik <[email protected]> - * under sponsorship from the FreeBSD Foundation. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * - * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND - * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE - * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL - * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS - * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) - * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT - * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY - * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF - * SUCH DAMAGE. - * - * $FreeBSD$ + * Written by Mateusz Guzik <[email protected]> + * Public domain. */ -#include <machine/asm.h> -__FBSDID("$FreeBSD$"); - -ENTRY(bcmp) - cmpq $16,%rdx - jae 5f -1: - testq %rdx,%rdx - je 3f - xorl %ecx,%ecx -2: - movzbl (%rdi,%rcx,1),%eax - movzbl (%rsi,%rcx,1),%r8d - cmpb %r8b,%al - jne 4f - addq $1,%rcx - cmpq %rcx,%rdx - jz 3f - movzbl (%rdi,%rcx,1),%eax - movzbl (%rsi,%rcx,1),%r8d - cmpb %r8b,%al - jne 4f - addq $1,%rcx - cmpq %rcx,%rdx - jz 3f - movzbl (%rdi,%rcx,1),%eax - movzbl (%rsi,%rcx,1),%r8d - cmpb %r8b,%al - jne 4f - addq $1,%rcx - cmpq %rcx,%rdx - jz 3f - movzbl (%rdi,%rcx,1),%eax - movzbl (%rsi,%rcx,1),%r8d - cmpb %r8b,%al - jne 4f - addq $1,%rcx - cmpq %rcx,%rdx - jne 2b -3: - xorl %eax,%eax - ret -4: - movl $1,%eax - ret -5: - cmpq $32,%rdx - jae 7f -6: - /* - * 8 bytes - */ - movq (%rdi),%r8 - movq (%rsi),%r9 - cmpq %r8,%r9 - jne 4b - leaq 8(%rdi),%rdi - leaq 8(%rsi),%rsi - subq $8,%rdx - cmpq $8,%rdx - jae 6b - jl 1b - jmp 3b -7: - /* - * 32 bytes - */ - movq (%rsi),%r8 - movq 8(%rsi),%r9 - subq (%rdi),%r8 - subq 8(%rdi),%r9 - or %r8,%r9 - jnz 4b - - movq 16(%rsi),%r8 - movq 24(%rsi),%r9 - subq 16(%rdi),%r8 - subq 24(%rdi),%r9 - or %r8,%r9 - jnz 4b - - leaq 32(%rdi),%rdi - leaq 32(%rsi),%rsi - subq $32,%rdx - cmpq $32,%rdx - jae 7b - jnz 1b - jmp 3b -END(bcmp) - - .section .note.GNU-stack,"",%progbits +#define BCMP +#include "memcmp.S" diff --git a/lib/libc/amd64/string/memcmp.S b/lib/libc/amd64/string/memcmp.S index 0c8121f9d885..3e6df7966312 100644 --- a/lib/libc/amd64/string/memcmp.S +++ b/lib/libc/amd64/string/memcmp.S @@ -39,7 +39,11 @@ __FBSDID("$FreeBSD$"); #define ALIGN_TEXT .p2align 4,0x90 /* 16-byte alignment, nop filled */ +#ifdef BCMP +ENTRY(bcmp) +#else ENTRY(memcmp) +#endif xorl %eax,%eax 10: cmpq $16,%rdx @@ -143,8 +147,25 @@ ENTRY(memcmp) /* * Mismatch was found. - * - * Before we compute it we narrow down the range (16 -> 8 -> 4 bytes). + */ +#ifdef BCMP + ALIGN_TEXT +10320016: +10320000: +10081608: +10163224: +10163216: +10163208: +10040804: +80: +1: + leal 1(%eax),%eax + ret +END(bcmp) +#else +/* + * We need to compute the difference between strings. + * Start with narrowing the range down (16 -> 8 -> 4 bytes). */ ALIGN_TEXT 10320016: @@ -214,5 +235,6 @@ ENTRY(memcmp) subl %r8d,%eax ret END(memcmp) +#endif .section .note.GNU-stack,"",%progbits
